Novel clay mineral color developer for pressure sensitive recording paper and process for producing same
US4405371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1981 |
| Grant date | Sep 20, 1983 |
| Priority date | — |
| Expiry date | Jun 30, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M5/1555
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A color developer for pressure-sensitive recording paper which is derived from a clay mineral having a layer-structure composed of regular tetrahedrons of silica and which shows PA0 (A) the diffraction pattern attributable to the crystals of layer-structure composed of regular tetrahedrons of silica when subjected to an electron diffraction analysis, but PA0 (B) substantially no diffraction pattern attributable to the crystals of said layer-structure when subjected to an X-ray diffraction analysis, and which PA0 (C) contains as the constituting elements besides oxygen, at least silicon, magnesium and/or aluminum. This color developer is produced by acid-treating a clay mineral having a layer-structure composed of regular tetrahedrons of silica until its SiO.sub.2 content reaches 82-96.5% by weight on dry basis (drying at 105.degree. C. for 3 hours), contacting the resulting clay mineral, in an aqueous medium, with a magnesium and/or an aluminum compound or compounds which are at least partially soluble in said aqueous medium, neutralizing the system with an alkali or an acid to form hydroxide when the soluble compound or compounds employed are other than hydroxides, whereby introdu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.